The present invention relates to a pneumatic tire reinforcing member and which includes a device for spirally winding belt cap or layer tire reinforcing members on a building drum.
In the Japanese Patent Application No. 46746/86 filed on Mar. 3, 1986, the present applicant proposed a high-speed pneumatic tire in which belt cap or layer tire reinforcing members are spirally wound outside a belt layer in the radial direction of the tire. In the pneumatic tire, the tensile forces of the portions of the tire reinforcing members, which are wound on both the axial end portions of a building drum, are made higher than those of the other portions of the tire reinforcing members, which are wound on the axially central portions of the building drum, so that the portions of the pneumatic tire near both the side edges of the tread thereof are strongly wound. As a result, the diameters of the portions of the pneumatic tire near both the side edges of the tread thereof are prevented from abnormally increasing when the tire is very rapidly rotated in practical use so as to cause a high centrifugal force to act to the portions of heavy rubber mass.
However, a device for spirally winding the tire reinforcing members on the building drum while controlling the tensile forces of said the tire reinforcing members, to form the pneumatic tire, has not been proposed.